Effects of externally added sodium and potassium ions on the glycolytic sequence of Saccharomyces cerevisiae

Glycolytic sequence and respiration of Debaryomyces hansenii as compared to Saccharomyces cerevisiae

“…Fermentation requires an adequate balance between the oxidized and the reduced form of the nucleotide, particularly NADH + H + , which is not available under aerobiosis, as revealed by the low levels of the reduced nucleotide under aerobiosis in the presence of hydrogen peroxide. The decreased respiratory capacity of S. cerevisiae upon starvation may explain the results reported previously (Hommes, 1964; Maitra and Estabrook, 1967, Peña et al , 1967) and the differences presented in Figure 6, showing an immediate and large change in the reduction of NAD + upon the addition of glucose in fasted cells, which was not observed in non‐fasted cells of either yeast. In fact, Racker and Wu (1959) reported that in a reconstituted system from Ehrlich ascites tumour cells, lactate production could be strongly reduced by the inclusion of adequate amounts of mitochondria from the same cells.…”

“…Since the effects of oxygenation produced important changes in the production of ethanol in both yeasts, and on glucose consumption in S. cerevisiae , the changes in NADH + H + levels were followed by changes in fluorescence at 340–460 nm, which may also provide information about the behaviour of glycolysis in yeasts (Hommes, 1964; Maitra and Estabrook, 1967). Experiments performed in fasted S. cerevisiae cells (Peña et al , 1967; Maitra and Estabrook, 1967); (Figure 6A) showed that immediately after glucose addition a rapid increase in fluorescence occurred, when the reduced nucleotide is produced at the level of glyceraldehyde 3‐phosphate dehydrogenase, followed by a rapid decrease once acetaldehyde starts to be produced, and then by a slow increase due to ethanol accumulation. When glucose was not added, practically no changes of fluorescence were seen.…”

“…Since the effects of oxygenation produced important changes in the production of ethanol in both yeasts, and on glucose consumption in S. cerevisiae, the changes in NADH + H + levels were followed by changes in fluorescence at 340-460 nm, which may also provide information about the behaviour of glycolysis in yeasts (Hommes, 1964;Maitra and Estabrook, 1967). Experiments performed in fasted S. cerevisiae cells (Peña et al, 1967;Maitra and Estabrook, 1967); ( Figure 6A) showed that immediately after glucose addition a rapid increase in fluorescence occurred, when Cell-free extracts were prepared from the cells by grinding with glass beads in the presence of a protease inhibitor cocktail and centrifuging at 5000 × g for 10 min. All activities are expressed as nmoles substrate converted (min/mg protein).…”

In situ study of K+ transport into the vacuole of Saccharomyces cerevisiae

“…The loss of the glycolytic capacity in permeabilized spheroplasts was also important, because it eliminates the possible interference of this pathway on the studies of vacuolar transport. This was also shown by the failure to observe a substantial reduction of endogenous NAD + by fluorescence at 340–460 nm (Peña et al , 1967) upon the addition of glucose (not shown), which allowed to concluding that the abatement of the glycolytic capacity in spheroplasts of both strains was due to the loss of most of the cytosolic nucleotides, including NAD + .…”

“…K + is a fundamental cation for the yeast and it is stored at a high concentration into the vacuole (Klionsky et al , 1990). Its transport and accumulation requires an important amount of energy, as well as changes of the internal pH of yeast (Peña et al , 1967; Ramírez et al , 1996; Calahorra et al , 1998). Its transport through the plasma membrane has been extensively studied (Wadskog and Adler, 2003); however, little is known about K + transport in the vacuole.…”